Functional orthotic support structure for footwear

ABSTRACT

An orthotic support structure or shell may be used with footwear intrinsically or as a removable and transferable device. The footwear may be a sandal assembly including a sole, a strap and an orthotic shell. The strap is attached to the sole and configured to secure the sole against the foot. The orthotic shell is positioned within the sole and formed from a semi-rigid material. The orthotic shell includes a heel portion configured to support a heel region of the foot, and a midfoot portion connected to the heel portion and configured to support an arch region of the foot, the midfoot portion comprising an arched shank having a curved convex shape. The arched shank is configured to deflect under a downward force applied thereon which reactively rotates the heel portion toward the heel region of the foot.

PRIORITY AND CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. application Ser.No. 16/459,376, filed Jul. 1, 2019, which is a Continuation Applicationof International Application No. PCT/US2019/017550, filed Feb. 11, 2019,which claims priority to U.S. Provisional Patent Application No.62/630,518 filed Feb. 14, 2018, the disclosure of which is herebyincorporated by reference in its entirety herein.

BACKGROUND Field

The present disclosure relates to an orthotic support structure, such asfor example a shell, fitted to the sole of footwear, such as forexample, a flip-flop style light sandal. The orthotic shell providesstructure to the sole such that the sole conforms to the shape of theorthotic shell and provides orthotic foot support to a wearer of thefootwear.

Description of Related Art

Flip-flop sandals are a popular and fashionable form of casual footweardue to their simple construction, low cost and minimalist aesthetics.Generally, the sole of a flip-flop is thin, flat and does not providesubstantial orthotic support to the foot of the wearer. As a result,regular and prolonged wearing of flip-flops can cause short andlong-term musculoskeletal damage resulting in osteoporosis, arthritis,shin splints, unstable gait, foot pain, knee pain, Achilles tendinitis,posterior tibial tendinitis, piriformis syndrome, plantar fasciitis, hippain, lower back pain, hammertoes, bunions, stress fractures,capsulitis, metatarsalgia, subluxation syndrome, neuromas, bursitis,corns, callouses, heel fissures, peroneal tendinitis, extensortendinitis and many other conditions.

SUMMARY

Typical footwear (e.g., sandals, shoes, boots) is designed with littleor no attention to providing proper functional, mechanical and dynamicsupport to the wearer's foot. This is particularly true for wearers whomay have abnormalities or deformities. Such problems can be addressedusing functionally biomechanical orthotic inserts (also referred to as“orthotics”), which are devices placed in footwear to cooperate with theplantar surfaces of a wearer's feet to provide various levels of supportand motion control to enhance comfort and/or compensate for footabnormalities or deformities and/or prevent their development orprogression.

Typically, in order to be effective, orthotics must be custom made. Whengeneric, they are addressing over-pronation or over-supination(cavus/planus foot types), but not both and if supportive, cannot allowfor “mobile adaptation”. To accommodate a spectrum of structural foottypes, generic orthotics are soft, insufficiently supportive, orcontoured, or functional and simply act as soft “arch supports”. Inaddition to these drawbacks, foot wear, such as sandals, with intrinsicorthotic design are challenged in providing adequate biomechanicalcontrol due to the loss of foot contact with the sandal during gaitwhich causes abnormal compensatory biomechanics such as toeflexion/extension and/or foot abduction/adduction, hipextension/flexion, increased cadence, shortened stride and or adjustingfoot strike pattern, etc.

The orthotic shell herein (interchangeably referred to herein as an“orthotic device”) provides prolonged dynamic contact with the wearer'sfoot allowing for a more true biomechanical and adaptability controlthat may be applied to a wide range of footwear, including withoutlimitation, athletic shoes, casual shoes, dress shoes, work boots andrecreational footwear.

The footwear having orthotic shell described herein is configured toprovide enhanced support and may compensate for various footabnormalities or deformities in a particularly robust and durable formfactor without need for adjustment or customization. The orthoticdescribed herein is a dynamic, functional orthotic that allows the footto function as a “mobile adapter” while adhering to biomechanical footprinciples and incorporates the Spiraldynamic™ theory of foot function.It controls the heel frontal plane motion and allows for adaptableforefoot variances (varus/valgus) by accommodating the medial andlateral foot columns while supporting the transverse arch of the foot.At least one embodiment of the footwear having an orthotic insole may besummarized as a composite sole structure including an orthotic shellreceived between insole platform and an outsole. The orthotic shell maybe completely enclosed between the insole platform and the outsole suchthat the orthotic shell is not externally visible when the footwear iscompletely assembled. The orthotic shell is preferably about two-thirds,three-quarters, four-fifths or more of an entire longitudinal length ofthe footwear and made of a semi-rigid material that is relatively morerigid than a material of the insole platform. The orthotic shellincludes a heel portion to support a heel of a foot of a wearer and aforefoot portion to support a forefoot of the wearer at least in aregion behind and near metatarsal heads of the foot and the transversearch of the foot. The orthotic shell may be shaped to support thecentral three metatarsal heads in a neutral, generally horizontalposition while supporting the transverse arch.

The orthotic shell may include a shank positioned between the heel cupand the metatarsal arch. In some embodiments, the shank may include aflexible extension angled at 15-30 degrees. The shank is curved in sucha way as to act dynamically in during gait so as to provide a closer andmore prolonged interface between the wearer's heel and the heel cup ofthe footwear. This allows a more natural gait and adaptable footfunction particularly in a sandal due to better and prolonged contactand less need for compensatory foot/gait adjustment such as shortenedstride, rearfoot instability (excessive inversion or eversion),increased cadence and toe flexion/extension and or footadduction/abduction.

In some embodiments, the footwear includes an outsole platform and afull-length insole sandwiching an orthotic midsole. An upper or vamp inthe form of retention straps are providing for holding the sandal to thefoot of the wearer. The retention straps may be formed from a materialfeaturing multi-directional stretching capability to provide enhancedcomfort and durability and contact. The insoles can include treadpatterns thereon to enhance traction between the sandal and a ground orother surface. The outsole platform and other components of thecomposite sole are sized to comfortably receive a wearer's foot of agiven size (e.g., size 10 or 11). The outsole platform is preferablymade of a generally flexible yet resilient, shock absorbing material,such as, for example, ethylene vinyl acetate (EVA), polyvinyl chloride(PVC), thermoplastic elastomers (TPE), rubber or similar siliconeblended materials.

An orthotic midsole in the form of an orthotic shell is received betweenthe outsole platform and the full length insole and supported in adetermined orientation. The orthotic shell is preferably abouttwo-thirds, three-quarters, four-fifths of a longitudinal length of thefootwear as illustrated, however, longer or shorter orthotic shells maybe used. The orthotic shell includes a heel portion to support a heel ofa foot of a wearer and a forefoot portion to support a forefoot of thewearer behind and near the central three metatarsal heads of the foot. Acentral shank or midfoot portion extends between the heel portion andthe forefoot portion. The shank portion acts in a dynamic way to allowfor a more prolonged heel contact through the wearers midstance andcurved to provide a similar advantage in the swing phase of the wearer'sgait. The midfoot portion generally corresponds to the plantar surfacesof a typical wearer's midfoot, including, for example, an arch of thefoot.

The orthotic shell is shaped such that, when it is supported at thedetermined orientation, the heel portion partially cups the wearer'sheel to support the same in a generally vertical orientation at or nearsub-talar joint neutral position. Simultaneously, the forefoot portionsupports the forefoot and transverse arch such that the central threemetatarsal heads are supported in a neutral, generally horizontalmanner. The orthotic shell may vary in shape, thickness, flexibility,material and other aspects. It is preferably made of a material having agreater stiffness than a material of the outsole platform. Further, theorthotic shell may have a rigidity that is greater than the outsoleplatform which may provide shock absorption. It may be affixed betweenthe outsole platform and full-length insole with adhesives or the like,or may be part of a midsole composite or apparatus. It may besubstantially entirely enclosed between the full-length insole and theoutsole platform such that the orthotic shell is not externally visiblewhen the sandal is completely assembled and injection molded. Thefull-length insole covering the orthotic shell may include surfacetexture or design features such that the sandal has a comfortable feelwhen worn.

In some embodiments, the orthotic shell received in the sandal may beshaped and oriented to support the forefoot and transverse arch of thewearer relative to the heel to stabilize the forefoot in a forefootvalgus position or a forefoot varus position, rather than a neutralforefoot position. In other embodiments, a portion of the midsoleplatform itself may vary progressively in thickness from one side of theinsole platform toward the other to simulate a forefoot valgus orforefoot varus wedge in order to allow the sub-talar joint to rest orfunction at or near neutral position.

The various aspects and features described above and other aspects andfeatures described herein may be combined to provide footwear that isparticularly well adapted to support the foot of a wearer in a stablemanner while also allowing the foot to flex and adapt naturally duringuse. Although embodiments have been shown and described herein as asandal or components for a sandal, it is appreciated that aspects andfeatures of the embodiments may be applied to a wide range of footwear,including without limitation, athletic shoes, casual shoes, dress shoes,work boots and recreational footwear or as a removable and transferableorthotic device.

In some embodiments, a method of making footwear may include enclosingan orthotic shell between an outsole platform and an insole. The insolegenerally extends about an entire longitudinal length of the footwearand the orthotic shell generally extending about two-thirds,three-quarters, four-fifths or more of the entire longitudinal length ofthe footwear. The orthotic shell has a heel portion to support a heel ofa foot of a wearer's foot, a forefoot portion to support a forefoot ofthe wearer's foot at least in a region behind and near the three centralmetatarsal heads of the foot and a midfoot dynamic “shank” portion therebetween and an angled sulcus extension to provide a prolonged heelcontact to the wearer's foot throughout gait as well as support amidfoot of the wearer's foot. This device may reduce compensatory gaitabnormalities associated with reduced foot contact to an orthotic sandalor other footwear, including without limitation, athletic shoes, casualshoes, dress shoes, work boots and recreational footwear or as aremovable and transferable orthotic device.

A sandal assembly for a foot of a wearer is provided. The sandalassembly includes a sole, a strap attached to the sole and configured tosecure and/or at least partially position the sole against the foot, andan orthotic shell positioned within the sole and formed from asemi-rigid material and/or a material that is more rigid than the sole.The orthotic shell includes a heel portion configured to support a heelregion of the foot, and a midfoot portion connected to the heel portionand configured to support an arch region of the foot, the midfootportion comprising an arched shank having a curved convex shape. Thearched shank is configured to deflect under a downward force appliedthereon which reactively rotates the heel portion toward the heel regionof the foot.

In some embodiments, deflection under the downward force applied thereonincreases a chord length of the arched shank in a longitudinal directionsuch that the increase in the chord length rotates the heel portiontoward the heel region of the foot.

In some embodiments, the heel portion rotates toward and applies a forceto the heel region of the foot at a midstance phase of gait.

In some embodiments, the heel portion further includes a concave heelcup. The heel can be flat “posted” to control frontal heel and/orsub-talar joint motion. The heel cup includes a base region configuredto support a bottom of the heel region, and a curved concave outersidewall region extending radially outward and upward from the baseregion in a direction away from the base region, the outer sidewallregion configured to support an outer periphery of the heel region.

In some embodiments, the heel portion is configured to rotate between 15degrees to 30 degrees at a heel-off phase of gait.

In some embodiments, the orthotic shell or orthotic device includes aforefoot portion connected to the midfoot portion and configured tosupport metatarsal heads and transverse arch of the foot.

In some embodiments, the midfoot portion and the forefoot region supportthe central three metatarsal of the foot.

In some embodiments, the sole includes an insole portion and an outsoleportion, wherein the orthotic device is positioned between the insoleand outsole portions.

In some embodiments, the orthotic device is enclosed within the sole.

In some embodiments, the orthotic device is more rigid than the soleand/or has a stiffness greater than a stiffness of the sole.

In some embodiments, the orthotic device is formed from plasticmaterial.

In some embodiments, the orthotic device has a thickness between 1 mm to5 mm.

In some embodiments, the orthotic device has a longitudinal length thatis between one-half to four-fifths of a longitudinal length of the sole.

In some embodiments, the orthotic device has a longitudinal length thatis greater than four-fifths of a longitudinal length of the sole.

In some embodiments, the orthotic device further comprises a distalextension portion connected to the forefoot portion and configured tosupport sulcus and plantar metatarsals of the foot.

In some embodiments, the distal extension portion is angled relative tothe forefoot portion.

In some embodiments the orthotic is removable and transferable.

A sole for footwear worn on a foot of a wearer is provided. The soleincludes an insole portion, an outsole portion positioned on a side ofthe insole portion that is opposite the foot of the wearer, an orthoticshell formed from a semi-rigid material (and/or a material that is morerigid than the sole) and positioned between the insole portion and theoutsole portion. The insole can include a side configured to contact thefoot of the wearer with an outsole portion positioned on another side ofthe insole portion that is opposite the side configured to contact thefoot. The orthotic shell includes a heel portion configured to support aheel region of the foot, and a midfoot portion connected to the heelportion and configured to support an arch region of the foot, themidfoot portion comprising an arched shank having a curved convex shape.The arched shank is configured to deflect under a downward force appliedthereon which reactively rotates the heel portion toward the heel regionof the foot.

An orthotic device for footwear worn on a foot of a wearer is provided.The orthotic device includes a heel portion configured to support a heelregion of the foot, and a midfoot portion connected to the heel portionand configured to support an arch region of the foot, the midfootportion comprising an arched shank having a curved convex shape. Thearched shank is configured to deflect under a downward force appliedthereon which increases a chord length of the arched shank in alongitudinal direction. The increase in the chord length causes reactiverotation of the heel portion toward the heel region of the foot.

In some embodiments, in use, the orthotic shell is enclosed within asole for footwear worn on a foot of a wearer.

In some embodiments, the orthotic shell is more rigid than the sole.

In some embodiments, the sole further includes an insole portion and anoutsole portion, wherein the orthotic shell is positioned between theinsole and outsole portions.

In some embodiments, the orthotic shell has a longitudinal length thatis between one-half to four-fifths of a longitudinal length of the sole.

In some embodiments, the orthotic shell has a longitudinal length thatis greater than four-fifths of a longitudinal length of the sole.

A method for manufacturing a sole that provides dynamic orthotic supportto a foot of a wearer is provided. The sole has an insole portion and anoutsole portion. The method includes providing a semi-rigid orthoticshell having a rigidity that is greater than the insole portion and theoutsole portion, positioning the orthotic shell between the insoleportion and the outsole portion, bonding the insole portion to theoutsole portion such that the orthotic shell is enclosed within thesole, and conforming a shape of the insole portion according to a shapeof the orthotic shell.

A method for providing dynamic orthotic support to a foot of a wearer bya sole of a footwear device fitted with a semi-rigid orthotic shell isprovided. The semi-rigid orthotic shell has a rigidity that is greaterthan the sole. The orthotic shell includes a heel portion and a midfootportion. The method includes applying a downward force on the midfootportion of the orthotic shell, bending the midfoot portion in responseto applying the downward force on the midfoot portion of the orthoticshell, and reactively rotating the heel portion of the orthotic shelltowards the foot in response to the bending of the midfoot portion. Thereactively rotating heel portion of the orthotic shell presses the soleagainst the foot to provide dynamic orthotic support to the foot of thewearer which is then prolonged with the forefoot loading to an angledsulcus extension. The method can include performing any of the functionsand/or steps associated with the features discussed above.

A method for manufacturing an orthotic shell that provides dynamicorthotic support to a foot of a wearer is provided. The method comprisesforming a concave region that is configured to support a heel region ofthe foot, and forming a convex region at an end of the concave region,the convex region being configured to support an arch region of thefoot. The convex region is configured to deflect under a downward forceapplied thereon which increases a chord length of the convex region in alongitudinal direction. The increase in the chord length causes reactiverotation of the concave region toward the heel region of the foot. Themethod can include manufacturing any of the features discussed above.

The foregoing is a summary and contains simplifications, generalization,and omissions of detail. Those skilled in the art will appreciate thatthe summary is illustrative only and is not intended to be in any waylimiting. Other aspects, features, and advantages of the devices and/orprocesses and/or other subject matter described herein will becomeapparent in the teachings set forth herein. The summary is provided tointroduce a selection of concepts in a simplified form that are furtherdescribed below in the Detailed Description. This summary is notintended to identify key features or essential features of any subjectmatter described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present disclosure will becomemore fully apparent from the following description, taken in conjunctionwith the accompanying drawings. Understanding that these drawings depictonly some embodiments in accordance with the disclosure and are,therefore, not to be considered limiting of its scope, the disclosurewill be described with additional specificity and detail through use ofthe accompanying drawings.

FIG. 1 is a perspective view of an example embodiment of a left orthoticshell.

FIG. 2 illustrates an embodiment of a left orthotic shell in thesagittal plane.

FIG. 3 illustrates an embodiment of a left orthotic shell in thetransverse plane.

FIG. 4A is a perspective view of footwear without an orthotic shellinstalled.

FIG. 4B illustrates the footwear in the transverse plane without anorthotic shell installed.

FIG. 4C illustrates the footwear in the sagittal plane without anorthotic shell installed.

FIG. 5 is an exploded view illustrating an embodiment of a left orthoticshell in the sagittal plane positioned between an insole portion and anoutsole portion of the footwear of FIGS. 4A-4C.

FIG. 6 illustrates the footwear in the transverse plane fitted with anembodiment of the orthotic shell to illustrate the position of theorthotic shell relative to the sole.

FIG. 7 illustrates the footwear fitted in the sagittal plane with anembodiment of the orthotic shell to illustrate the shape and contour ofthe sole.

FIG. 8 illustrates the footwear in the sagittal plane fitted with anembodiment of the orthotic shell to illustrate the orthotic supportprovided by the sole at the midstance phase of a wearer's gait.

FIG. 9 illustrates the footwear in the sagittal plane fitted with anembodiment of the orthotic shell to illustrate the orthotic supportprovided by the sole at the terminal stance (heel-off) phase of thewearer's gait.

FIG. 10 is a close-up view of the heel portion of the footwear in thesagittal plane fitted with an embodiment of the orthotic shell toillustrate the maximum angle of rotation by the heel cup of the sole.

FIG. 11 illustrates the footwear in the sagittal plane without theorthotic shell installed at the terminal stance (heel-off) phase of thewearer's gait.

FIG. 12A illustrates an embodiment of the orthotic shell in thetransverse plane with the heel cup rotated toward the lateral side ofthe orthotic shell.

FIG. 12B illustrates an embodiment of the orthotic shell in thetransverse plane with the heel cup rotated toward the medial side of theorthotic shell.

FIG. 12C illustrates an embodiment of the orthotic shell in thetransverse plane with the heel cup rotated either toward the medial sideor toward the lateral side of the orthotic shell.

FIG. 13 illustrates dorsiflexion and plantarflexion of the ankle versusthe neutral position of the ankle.

FIG. 14 illustrates an example embodiment of the transverse, frontal andsagittal planes.

FIG. 15 illustrates abduction and adduction of the foot versus a neutralposition.

FIG. 16 illustrates rotation or inversion/eversion movement of the footand/or leg in the frontal plane. Right foot from posterior.

FIG. 17 illustrates an alternative embodiment of the orthotic shellviewed in the sagittal plane, the orthotic shell provided with a distalextension portion.

FIGS. 18A-18H show images of an embodiment of a Soloha orthotic.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative embodiments described in thedetailed description and drawings are not meant to be limiting. Otherembodiments may be utilized, and other changes may be made, withoutdeparting from the spirit or scope of the subject matter presented here.It will be readily understood that the aspects of the presentdisclosure, as generally described herein, and illustrated in thefigures, may be arranged, substituted, combined, and designed in a widevariety of different configurations, all of which are explicitlycontemplated and made a part of this disclosure

Civilizations throughout the world have used flip-flop style lightsandals as a simple and convenient form of footwear. In recent years,flip-flops such as those manufactured by, for example, Havaianas™,Ipanemas™ and Old Navy™ have become one of the most popular forms ofcasual footwear. As a result, flip-flops have transcended beyond pool-and beach-appropriate footwear and have become a fashionable form offootwear for casual everyday use. In warmer climate regions, flip-flopsare now the most common form of footwear.

Flip-flops have a simple design that is typically comprised of very fewcomponents. For example, as shown in FIGS. 4A-4C, shoes or footwear 12,such as a flip-flop sandal as illustrated as an embodiment, may comprisea thong or Y-shaped strap 14 that is anchored to a molded flat sole 16.Typically, the sole 16 is formed from rubber, PVC, leather or EVA foam.The Y-shaped strap is positioned between the first and second toes andthe flip-flop is held loosely onto the foot. Due to their simple design,flip-flops are inexpensive to manufacture relative to other forms offootwear, which further expands their appeal worldwide.

As a consequence of their simple design, flip-flops typically fail toprovide adequate orthotic support and stability to the wearer's feet.That is, the soles of flip-flops are typically flat and therefore failto provide adequate heel and arch support, if any. As a result,flip-flop wearers may suffer muscular and skeletal ailments to theirlower extremities (e.g., foot, ankle, knees, etc.) such as, for example,plantar fasciitis, gait issues, arthritis, lower back pain and sciatica.

Flip-flops are typically worn loosely on the foot, which allow them tobe quickly and easily donned and doffed. However, loose fitment offlip-flop also causes the toes to reactively prevent the flip-flop fromfalling of the foot during the swing phase of gait. That is, when aflip-flop dangles freely from the top of a foot during the swing phaseof gait, the wearer typically curls his/her toes to grasp and hold thecenter post of the Y-shaped strap to ensure that the flip-flop does notfall off the foot. Over time, the repeated grasping and curling of thetoes may cause hammertoes, neuromas, contraction deformities andbunions. Further, the wearer may also shorten his/her stride andexperience excessive ankle plantarflexion or dorsiflexion. Forreference, FIGS. 12A-12C illustrate ankle dorsiflexion 150 andplantarflexion 152 of the foot 2 versus the neutral position 144 of thefoot 2.

Enhanced flip-flops have been developed to address the inadequacies ofthin flat-soled flip-flops. Enhanced flip-flops provide a thicker,multi-density and ergonomically contoured sole that is intended toovercome the lack of support provided by flip-flops. The ergonomicallycontoured sole is shaped to provide increased heel and arch support,relative to a thin flat-soled flip-flop. Additionally, enhancedflip-flops may include additional heel straps that fasten the heel tothe flip-flop to prevent separation of the heel and the heel portion ofthe sole. Further, enhanced flip-flops are typically much heavier thanor relative to flat-soled flip-flops which then adds to the adverseeffects during swing phase of gait.

Generally, enhanced flip-flops improve the biomechanics of thinflat-soled flip-flops by providing increased cushioning and orthoticsupport. However, enhanced flip-flops may cost five to ten times morethan flat-soled flip-flops and still not provide the features andfunctionality disclosed herein. Further, the thicker contoured sole andadditional straps of enhanced flip-flops provide a bulky and complicatedaesthetic that is in stark contrast with the fashionable minimalisticaesthetic provided by the flat-soled flip-flops. Therefore, a needexists for a means for providing improved biomechanics to thinflat-soled flip-flops that can exceed even that of enhanced sandals andbenefit various foot types.

FIGS. 1-3 illustrates an orthotic support structure, case, frame,framework, insert, insole, midsole, device or shell 10 of the presentdisclosure. In use, the orthotic device or shell 10 is fitted within thesole 16 of the shoe or footwear 12, such as a thin flat-soled flip-flop,as shown in FIGS. 5-10. While this disclosure is discussed in thecontext of a flip-flop sandal, features of the orthotic shell 10 may beapplied and used in other footwear, including other open type footwearor closed type footwear, such as sandals, slip-on type shoes, booties,sneakers, etc. As will be described in further detail below, when fittedwith the orthotic shell 10, the sole 16 of the footwear 12 conformssubstantially to the contoured shape of the orthotic shell 10 such thatthe sole 16 provides orthotic support to the foot at the initial contact(e.g., heel-strike) through midstance (e.g., foot-flat) phases of gatewhile allowing the foot mobile adaptability of the medial and lateralcolumns of the foot. Further, the orthotic shell 10 causes the sole 16to dynamically and reactively bend and deflect under load such that thesole 16 actively supports the foot at the terminal stance (e.g.,heel-off) phase of gate. Accordingly, the orthotic shell 10 may be usedin any type of shoe where orthotic support to the foot at the initialcontact (e.g., heel-strike) through midstance (e.g., foot-flat) phasesof gate and prolonging the contact with dynamic deflection with a distalextension angled at the plantar metatarsal head and sulcus region of thefoot can be beneficial. For example, while not limited to, footwear thatis lightweight and/or has a sole conformed to the orthotic shell 10where extended heel support is desired as discussed herein can be usedwith the orthotic shell 10.

The shank is arched lateral to medial to the contour of the transversearch. The medial arch is slightly higher than the lateral to contour tothe foot.

The distal shank is longer on the medial side to conform to themetatarsal head parabola of the foot.

As illustrated in FIGS. 5 and 6, the orthotic shell 10 has alongitudinal length that is roughly four-fifths of the length of anentire longitudinal length of the sole 16 of the flip-flop 12. That is,as shown, the orthotic shell 10 has a length Los and the sole 16 of theflip-flop 12 has a length LFF. In some embodiments, the length Los maybe roughly four-fifths of the length LFF. In some embodiments, theorthotic shell 10 may have a longitudinal length that is one-half tofour-fifths of the length of an entire longitudinal length of the sole16, including the foregoing values and ranges bordering therein. Inother embodiments, the orthotic shell 10 may have a longitudinal lengththat is less than one-half (e.g., one-third to one-half) or greater thanfour-fifths (e.g., four-fifths to a full length) of the length of anentire longitudinal length of the sole 16, including the foregoingvalues and ranges bordering therein.

When fitted within the sole 16, the orthotic shell 10 supports the footfrom the calcaneus (e.g., heel bone region) to a region near themetatarsal heads. In some embodiments, the orthotic shell 10 extends toa region at or rearwards of the metatarsal heads. That is, the phalangesof the foot are not supported by the orthotic shell 10. In otherembodiments, the orthotic shell 10 extends to a region forward of themetatarsal heads. The orthotic shell 10 may vary in longitudinal lengthdepending on the length of the flip-flop 12 such that orthotic shell 10accommodates various flip-flop sizes and foot proportions. Similarly,the orthotic shell 10 may vary in lateral width depending on the widthof the flip-flop 12 such that orthotic shell 10 accommodates widths formen, women and children.

The orthotic shell 10 is formed from a semi-rigid material such as, forexample but not limited to, plastic, resin or reinforced compositematerials. The orthotic shell 10 may be formed by molding or formingtechniques such as, but not limited to, injection molding,thermoforming, vacuum forming, milling, 3D printing, etc. In someembodiments, the orthotic shell 10 is formed from polypropylene orpolyethylene with a uniform thickness of 2 mm to 3 mm (millimeter(s)(mm)) substantially throughout its longitudinal length and lateralwidth, including the foregoing values and ranges bordering therein. Inother embodiments, the orthotic shell 10 may have a thickness less than2 mm (e.g., 1 to 2 mm) or greater than 3 mm (e.g., 3 to 4 mm).

Preferably, the orthotic shell 10 is relatively more rigid than the sole16 of the flip-flop 12 such that the sole 16 of the flip-flop 12conforms substantially to the contoured shape of the orthotic shell 10.In some embodiments, the sole 16 may comprise multiple layers such as aninsole portion and an outsole portion. The orthotic shell 10 may be morerigid than both the insole portion 18 and the outsole portion 20. Insome embodiments, the orthotic shell 10 may be more rigid than at leastone of the insole portion 18 or the outsole portion 20. In someembodiments, the orthotic shell 10 may be more rigid than at least onelayer or portion of the insole portion 18 and/or the outsole portion 20.It should be understood to one of ordinary skill in the art that therigidity of the orthotic shell 10 and the sole 16 may vary relative toother portions of each of the orthotic shell 10 and the sole 16 and/orto each other such that the orthotic support provides the desiredorthotic support to the foot of the wearer.

In some embodiments, the orthotic shell 10 is formed from a materialthat has an elastic modulus greater than the material used to form thesole 16. For example, typically, the sole of flip-flops is formed fromEVA foam. Accordingly, in some embodiments, the orthotic shell 10 isformed from a material that has an elastic modulus greater than EVAfoam.

Overview

With reference to FIG. 1-3, the orthotic shell 10 is comprised of a heelportion 22, a midfoot portion 24 and a forefoot portion 26. The heelportion 22 is configured to support the heel region of the foot. Themidfoot portion 24 is configured to support the midfoot region of thefoot. The forefoot portion 26 is configured to support the forefootregion of the foot. The total construct supports the heel, midfoot,transverse arch and medial arch while allowing for medial and lateralcolumn adaptation.

The heel portion 22 comprises a rear portion 52 and a front portion 54.The heel portion 22 is attached to an end of the midfoot portion 24 thatis opposite the forefoot portion 26. That is, the front portion 54 ofthe heel portion 22 is connected to a rear portion 56 of the midfootportion 24. FIG. 3 illustrates an approximate boundary line 70 betweenthe front portion 54 of the heel portion 22 and the rear portion 56 ofthe midfoot portion 24 along which the heel portion 22 and the midfootportion 24 are connected. The heel portion 22 comprises a heel cup 30that supports the heel region of the foot. As shown, the heel cup 30 hasa concave shape that corresponds to the rounded shape of the heel of thefoot. The heel cup 30 may comprise a substantially flat or planar centerbase region 32 that is surrounded by a curved concave outer sidewallregion 34 that extends radially outward and upward in a direction awayfrom the sole of the flip-flop. That is, the outer sidewall region 34extends outward and upward from the base region 32 of the heel cup 30toward the heel of user. The base region 32 is configured to support thebottom or base of the heel (i.e., the heel bone region of the foot). Theouter sidewall region 34 is configured to support the outer periphery ofthe heel region during the stance phases of gate. The outer sidewallregion 34 also aligns the heel portion 22 as it receives the heel uponthe heel-strike phase of gait such that orthotic shell 10 issubstantially aligned with the foot prior to the stance phases of gate.

The midfoot portion 24 comprises a rear portion 56 and a front portion58. The rear portion 56 of the midfoot portion 24 is attached to thefront portion 54 of the heel portion 22 which may be angled 15-45degrees in the sagittal plane, and to the front portion 58 is attachedto a rear portion 60 of the forefoot portion 26.

The midfoot portion 24 comprises an arched shank 40 that extends betweenthe heel portion 22 and the forefoot portion 26. The arched shank 40 hasa curved convex shape from lateral to medial and distal to proximal thatcorresponds to and supports the plantar surfaces of the foot including,for example, the metatarsals and transverse arch of the foot. A rearportion 56 of the midfoot portion 24 is connected to a front portion 54of the heel cup 30. In some embodiments, the arched shank 40 isconnected to the base region 32 at an inflection point between theconvex curvature of the arched shank 40 and the concave curvature of thebase region 32. It is at this point where the heel portion is angled15-45 degrees to the proximal shank portion. As shown in FIG. 2 (seealso FIG. 3), the convex arch may be higher on a medial side 42 than ona lateral side 44 of the arched shank 40 in substantial conformity withthe medial and lateral longitudinal arches of the foot. That is, theheight of the convex arch on a medial side 42 may be greater than theheight of the convex arch on a lateral side 44. In some embodiments, thelateral side 44 of the arched shank 40 may be substantially flat.

As shown in FIG. 3, the midfoot portion 24 varies in lateral width alongits longitudinal length. The width of the arched shank 40 is narrower atan end adjacent to the heel cup 30 and increases along its length towardthe forefoot portion 26. The rear portion 56 of the midfoot portion 24may have a width W₁ that increases to a width W₂ at the front portion 58of the midfoot portion 24. The arched shank 40 expands in width suchthat the three central metatarsal of the foot are supported along theirlength by midfoot portion 24. In some embodiments, the width W₁ of thearched shank 40 at the rear portion 56 of the midfoot portion 24 may besubstantially similar to the width of the base region 32. In someembodiments, the width W₂ of the arched shank 40 at the front portion 58of the midfoot portion 24 may be substantially similar to the width ofthe rear portion 56 of the forefoot portion 26.

The forefoot portion 26 comprises a rear portion 60 and a front portion62. The rear portion 60 of the forefoot portion 26 is attached to thefront portion 58 of the midfoot portion 24. FIG. 3 illustrates anapproximate boundary line 72 between the front portion 58 of the midfootportion 24 and the rear portion 60 of the forefoot portion 26 alongwhich the midfoot portion 24 and the forefoot portion 26 are connected.The front portion 62 defines an end of the orthotic shell 10.

The forefoot portion 26 supports the forefoot region of the foot suchthat the central three metatarsal are supported along their length andin the transverse arch. The forefoot portion 26 extends to a region nearthe three central metatarsal heads of the foot and may extend to aposition rearward, at or forward of the three central metatarsal heads.In some embodiments, the forefoot portion 26 supports the central threemetatarsal heads in a neutral, generally horizontal position. In otherembodiments, the forefoot portion 26 may support the central threemetatarsal in a forefoot valgus position or a forefoot varus position,rather than a neutral forefoot position. Further, with the forefootportion 26 supporting the three central metatarsals, the orthotic shell10 can accommodate foot deformities, such as forefoot valgus andforefoot varus, while still achieving the features and functionality ofthe orthotic shell 10 as discussed herein by not relying on contact orpressure from the outer metatarsals and allowing them to “float”. Thiscan be further accommodated by the rotational flexibility of the shankportion in the frontal plane. This can neutralize/accommodate forefootto rearfoot varus/valgus deformities and allow for normal mobileadaptability. In some embodiments, the midfoot portion 24 and/orforefoot portion 26 may be shaped to support the three centralmetatarsal and one or both outer metatarsals. In other embodiments, themidfoot portion 24 and/or forefoot portion 26 may be shaped to supportany combination of metatarsals in the foot.

In some embodiments, the orthotic shell 10 received in the footwear 12may be shaped and oriented to support the forefoot of the wearerrelative to the heel to stabilize the forefoot in a forefoot valgusposition or a forefoot varus position, rather than a neutral forefootposition. In other embodiments, a portion of the midsole platform itselfmay vary progressively in thickness from one side of the insole platformtoward the other to simulate a forefoot valgus or forefoot varus wedge.

Fitting of Orthotic Shell to Sole

FIGS. 4A-4C illustrate an exemplary thin flat-soled flip-flop 12 with aflat non-contoured sole 16. As illustrated in FIG. 4C, the sole 16 ofthe flip-flop 12 is comprised of an insole portion 18 and an outsoleportion 20. The insole portion 18 faces and contacts the foot and theoutsole portion 20 faces and contacts the ground. In some embodiments,the sole 16 may be unitary and formed from a material such as, forexample, EVA foam. In some embodiments, the sole 16 may comprise asassembly of a plurality of layers of foam, fabric and rubber.

FIG. 5 illustrates the flat-soled flip-flop 12 and the orthotic shell 10in the sagittal plane 158. As shown, the orthotic shell 10 is positionedbetween the insole portion 18 and the outsole portion 20. The heel cup30 of the orthotic shell 10 is positioned within and aligned with theheel portion 122 of the flip-flop 12 such that the heel is received andsupported by the heel cup 30. The arched shank 40 is positioned withinthe midfoot region 124 of the flip-flop 12 such that the central threemetatarsals are supported along their length by the arched shank 40. Theforefoot portion 26 is positioned within the forefoot region 126 of theflip-flop 12 such that the central three metatarsal heads are supportedby the forefoot portion 26 in a neutral, generally horizontal positionwhile contouring support of the transverse arch.

During assembly, in some embodiments, the orthotic shell 10 ispositioned between the insole portion 18 and the outsole portion 20which are then bonded together such that the orthotic shell 10 issandwiched between the insole portion 18 and the outsole portion 20. Thesole 16 may be assembled by bonding together the insole portion 18 theoutsole portion 20 by any mechanical means such as, but not limited to,adhesives, stitching, bonding, fasteners, etc. As a result, the orthoticshell 10 is retained between the insole portion 18 and the outsoleportion 20 and held within the sole 16. When the insole portion 18 isbonded to the outsole portion 20, the orthotic shell 10 may becompletely enclosed or substantially completely enclosed such that theorthotic shell 10 is not externally visible when the sole 16 is fullyassembled, as illustrated in FIGS. 6 and 7.

FIG. 7 illustrates the flip-flop 12 in the sagittal plane 158 after theorthotic shell 20 has been fitted to the sole 16. In contrast to FIG. 4Cwhich illustrates the sole 16 prior to fitting of the orthotic shell 10,the sole 16 illustrated in FIG. 7 has a shape and contour thatcorresponds to and matches that of the orthotic shell 10. As shown inFIG. 7, the heel portion 122, the midfoot portion 124 and the forefootportion 126 substantially conform to the shape and contours of the heelportion 22, the midfoot portion 24 and the forefoot portion 26 of theorthotic shell 10. Similarly, the sole 16 also comprises a heel cup 130and a midfoot arch region 140 that substantially conform to the shapeand contours of the heel cup 30 and the midfoot arch shank 40 of theorthotic shell 10. That is, the heel cup 130 has a concave shape thatcorresponds to the rounded shape of the heel region 4 of the foot 2.Similar to the orthotic shell 10, the heel cup 130 may comprise asubstantially flat or planar center base region 132 that is surroundedby a curved outer sidewall region 134 that extends and rises from thebase region 132. The arch region 140 has a curved convex shape thatcorresponds to and supports the plantar surfaces of the foot including,for example, the metatarsals and transverse arch of the foot.

The insole and outsole portions 18, 20 substantially conform to theshape of the orthotic shell 10 because the orthotic shell 10 has arigidity and/or stiffness greater than the sole 16. Accordingly, theinsole and outsole portions 18, 20, which are relatively more flexiblethan the orthotic shell 10, follow the contours of the less flexibleorthotic shell 10. As a result, the orthotic shell 10 provides aninternal frame, structure or backbone that shapes the insole and outsoleportions 18, 20.

Orthotic Support at Initial Contact and Midstance

FIG. 8 illustrates the flip-flop 12 fitted with and conforming to theshape of the orthotic shell 10. The flip-flop 12 is donned on a wearer'sfoot 2 at the midstance (foot-flat) phase of gait. As shown, the sole 16fitted with the orthotic shell 10 which provides orthotic support to theheel region 4 and the midfoot region 6 of the foot 2. The heel region 4of the foot 2 contacts and is supported by the heel cup 130 of the sole16. The midfoot region 6 of the foot 2 contacts and is supported by thearch region 140 of the sole 16.

Similar to the orthotic shell 10, the heel cup 130 of the sole 16receives the heel region 4 of the foot 2 such that the outer peripheryof the heel region 4 is substantially cupped and cradled by the heel cup130 at the initial contact (heel-strike) through the midstance(foot-flat) phases of gate. At the initial contact (heel-strike) phaseof gait, the curved outer sidewall region 134 of the heel cup 130 mayinitially engage the outer periphery of the heel region 4 as the heelregion 4 is approaching the sole 16 upon heel-strike. As the contactwith the outer periphery of the heel region 4 increases upon initialcontact (heel-strike), the curved outer sidewall region 134 increasinglyaligns the heel cup 130 with the heel region 4 of the foot 2 such thatheel region 4 is centered with the sole 16 as the heel region 4 isseated within the heel cup 130 at midstance (foot-flat).

The cradling and cupping of the heel region 4 of the foot 2 supports theouter periphery of the heel region 4 in the frontal (coronal),transverse and sagittal planes. For reference, FIG. 14 illustrates thefoot 2 with respect to the transverse plane 154, the frontal plane 156,and the sagittal plane 158. Supporting the heel region 4 in thetransverse plane 154, the frontal plane 156, and the sagittal plane 158may promote healthy biomechanics of the wearer's foot and ankles. Forexample, supporting the heel region 4 in the transverse plane 154, thefrontal plane 156, and the sagittal plane 158 may promote neutralalignment of the foot 2 and aid in preventing, inhibiting or mitigatingunder pronation (supination) and over pronation.

As discussed herein and with reference to FIG. 16, over pronation 128and under pronation 129 can refer to rotation of the foot 2 so that inthe corresponding anatomical position, the sole of the foot 2 is facinganteriorly (inverted) or posteriorly (everted). FIG. 14 illustrates thefoot 2 with respect to the frontal plane 156 in a neutral position 144,over pronation/everted 128 and under pronation/inverted 129.

The cradling and cupping of the heel region 4 may also maintainalignment of the heel portion 122 of the sole 16 with the heel region 4of the foot 2 upon each step of the wearer. Proper alignment of the foot2 with the sole 16 in the transverse plane 154, the frontal plane 156,and the sagittal plane 158 may improve the fitment, comfort andaesthetic of the flip-flop 12.

The arch region 140 of the sole 16 supports the midfoot region 6 of thefoot 2. Similar to the orthotic shell 10, the arch region 140 has acurved convex shape that corresponds to and supports the plantarsurfaces of the foot including, for example, the metatarsals andtransverse arch of the foot 2. Support of the metatarsals and transversearch may prevent collapse of the arch and flat-footedness and promoteinter-locking of the tarsal-metatarsal joint complex. This along withcontrolling frontal plane heel/sub-talar joint motion allows locking ofthe mid-tarsal joint so the foot can function as a rigid lever inpropulsion. Providing arch support as well as this biomechanical footcontrol may also alleviate or prevent plantar fasciitis and a multitudeof the aforementioned lower extremity ailments and improve the comfortof the flip-flop 12

Further, as shown in FIG. 8, the midfoot region 6 of the foot 2 appliesa substantially downward midstance arch force F_(MSA) onto the archregion 140 of the sole 16 during midstance (foot-flat). As previouslydescribed, the arch region 140 of the sole 16 is supported by thesemi-rigid arch shank 40 of the orthotic shell 10 within the sole 16.Accordingly, the midstance arch force F_(MSA) causes the convex archshank 40 and the convex arch region 140 to flatten such that the heightof the contour and/or the amount of convexity of both the arch shank 40and the arch region 140 decreases when compared to an unloaded state ofthe sole 16, as shown in FIG. 7. That is, the convex arch shank 40 iscompressed between the wearer's foot (i.e., which is applying themidstance arch force F_(MSA)) and the surface on which the sole 16 iscontacting (e.g., the ground) such that the convex arch region 140deforms and bends which decreases the convexity of the convex archregion 140. In some embodiments, the arched shank 40 and the convex archregion 140 retain a degree of convexity such that arch support isprovided by the sole 16 at midstance (foot-flat). That is, in someembodiments, the convex curvature of the arched shank 40 and the archregion 140 are not entirely flattened at midstance (foot-flat). Thedegree of convexity may be varied according to the material stiffness,rigidity, geometry and/or construction of each of the orthotic shell 10and sole 16.

As the convex curvature of the arch region 140 flattens and compressesunder the midstance arch force F_(MSA), the chord length of the convexcurvature of the arch region 140 in the longitudinal direction increasesfrom a chord length CL₀ in the unloaded state (shown in FIG. 7) to CL₁in the midstance loaded state (shown in FIG. 8). In some configurations,the difference in length between CL₁ and CL₀ may be between 1 mm to 5mm, including the foregoing values and ranges bordering therein. Inother embodiments, the difference in length between CL₁ and CL₀ may beless than 1 mm or greater than 5 mm, including the foregoing values andranges bordering therein.

As previously described, the rear portion 56 of the arched shank 40 isconnected to the front portion 54 of the heel cup 30. Therefore, as aresult of the flattening and increased chord length CL₁ of the convexarch region 140 under the midstance arch force F_(MSA) (i.e.,compression of the arched shank 40 between the wearer's foot and theground), the rear portion 56 of the arched shank 40 is displacedrearward and downward. Accordingly, the front portion 54 of the heel cup30 is also displaced rearward and downward. Further, the downwarddisplacement of the front portion 54 of the heel cup 30 causes the rearportion 52 of the heel cup 30 to be displaced upward. The upwarddisplacement of the rear portion 52 of the heel cup 30 causes the heelcup 30 to rotate upwards and towards the heel region 4 of the foot 2.That is, the downward and rearward movement of the front portion 54 ofthe heel cup 30 due to the increased chord length CL₁ of the convex archshank 40 in response to the midstance arch force F_(MSA) causes upwardmovement of the rear portion 52 of the heel cup 30 which rotates theheel cup 30 towards the heel region 4 of the foot 2.

Accordingly, as the structure of the sole 16 is provided by the orthoticshell 10, the dynamic rotation of the heel cup 30 of the orthotic shell10 in response to the midstance arch force F_(MSA) causes the heel cup130 of the sole 16 to rotate upwards and towards the heel region 4 ofthe foot 2. In some embodiments, the heel cup 30 may rotatesubstantially about the connection between the rear portion 56 of thearched shank 40 and the front portion 54 of the heel cup 30 such as theinflection point between the convex curvature of the arched shank 40 andthe concave curvature of the heel cup 30. In some embodiments, the heelcup 30 and the arched shank 40 may be connected along their respectiveends. As discussed herein, rotation of the heel cup 30 of the orthoticshell 10 causes rotation of the heel cup 130 of the flip-flop 12.Rotation of the heel cup 130 is indicated by the arrow R in FIG. 8.

With further reference to FIG. 8, the upward rotation of the heel cup130 pushes the center base region 132 in contact with the heel 4 of thefoot 2 and applies a midstance heel force F_(MSH) upon the heel region 4of the foot 2. The midstance heel force F_(MSH) presses the heel cup 130upward against the heel region 4 of the foot 2 such that the heel cup130 actively engages the heel region 4 at midstance (foot-flat). Thedynamic and active engagement of the heel region 4 increases thecradling and cupping effect of the heel cup 130 which further promotesproper alignment of the heel region 4 and healthy biomechanics of thewearer's foot and ankles. For example, the curved sidewall region 134can cause the heel region 4 to align into the heel cup 130 along atleast along the sagittal plane in midstance. Accordingly, the orthoticshell 10 can control foot 2 contact points and pressure along thesagittal plane in midstance via the heel cup 30 (and midfoot andforefoot portions 24, 26) as discussed herein. Further, the orthoticshell 10 via alignment and pressure of the heel cup 130 in midstance asdiscussed herein can control (e.g., substantially prevent or inhibit)roll of the foot 2 in the transverse plane relative to theorthotic/sandal.

Orthotic Support at Terminal Stance

FIG. 9 illustrates the flip-flop 12 fitted with the orthotic shell 10that is donned on a wearer's foot 2 at the terminal stance (heel-off)phase of gate. At terminal stance (heel-off), the weight of the weareris gradually shifted forward from the heel region 4 to the midfootregion 6 as the heel region 4 of the foot 2 is lifted off the heelportion 122 of the sole 16. That is, at terminal stance (heel-off),weight is increasingly shifted over the arch region 140 of the sole 16and less weight is positioned over the heel cup 130 until the heelregion 4 of the foot 2 is lifted entirely or substantially entirely away(i.e., heel-off) from the base region 132 of the heel cup 130 and theheel region 4 is not in contact with the sole 16.

Accordingly, the magnitude of the terminal stance arch force F_(TSA)applied by the midfoot region 6 of the foot 2 to the arch region 140 ofthe sole 16 at terminal stance (heel-off) may be greater than themagnitude of the midstance arch force F_(MSA) at midstance (flat-foot).The increase in magnitude between the terminal stance arch force F_(TSA)and the midstance arch force F_(MSA) causes further flattening of theconvex arch of the semi-rigid arched shank 40 and the arch region 140.

Whether or not the magnitude of the terminal stance arch force F_(TSA)increases, the heel lifting relative to the support surface in theterminal stance provides travel clearance, space, or room, includingroom for rotational movement, to allow at least a portion of the baseregion 132 of the heel cup 130 (and corresponding portions of thefootwear 12) to rise or translate generally upwards relative to thesupport surface due to the terminal stance arch force F_(TSA) asillustrated in FIG. 9 relative to FIG. 8. Thus, in some embodiments, theheel lifting relative to the support surface in the terminal stanceprovides room for rotational movement to allow at least a portion of thebase region 132 of the heel cup 130 (and corresponding portions of thefootwear 12) to rise or translate generally upwards relative to thesupport surface due to the terminal stance arch force F_(TSA) without anincrease in the magnitude of the terminal stance arch force F_(TSA). Insome embodiments, the heel lifting relative to the support surface inthe terminal stance provides room for rotational movement to allow atleast a portion of the base region 132 of the heel cup 130 (andcorresponding portions of the footwear 12) to rise or translategenerally upwards relative to the support surface due to the terminalstance arch force F_(TSA) with an increase in the magnitude of theterminal stance arch force F_(TSA).

Further flattening of the arch region (longitudinally but nottransversely) 140 at terminal stance (heel-off) causes the chord lengthof the convex curvature of the arch region 140 in the longitudinaldirection to further increase from the chord length CL₁ at the midstanceloaded state (shown in FIG. 8) to CL₂ at the terminal stance loadedstate (shown in FIG. 9). Therefore, as a result of the increased chordlength CL₂ of the further flattened arched shank 40, the front portion54 of the heel cup 30 is pushed or displaced further rearward anddownward which further rotates the heel cup 30 upwards and towards theheel region 4 of the foot 2 while maintaining transverse convex archsupport lateral to medial. Rotation of the heel cup 130 is indicated bythe arrow R in FIG. 9. In some configurations, the difference in lengthbetween CL₂ and CL₁ may be between 5 mm to 10 mm, including theforegoing values and ranges bordering therein. In other embodiments, thedifference in length between CL₁ and CL₀ may be less than 5 mm orgreater than 10 mm, including the foregoing values and ranges borderingtherein.

The further upward rotation of the heel cup 130 causes the center baseregion 132 to apply a terminal stance heel force F_(TSH) upon the heelregion 4 of the foot 2. The midstance heel force F_(TSH) activelypresses the heel cup 130 upward and against the rising heel region 4 ofthe foot 2 such that the heel cup 130 actively engages the heel region 4even as the heel region 4 is lifting upward between midstance andterminal stance. This dynamic and reactive rotation/movement of the heelcup 30 of the orthotic shell 10 causes the heel cup 130 of the sole 16to prolong the contact with and support of the rising heel region 4 ofthe foot 2 (i.e., relative to a flat-soled flip-flop not fitted with theorthotic shell 10) until the heel region 4 rises beyond the reach of theheel cup 130. The extended engagement of the heel region 4 of the foot 2as the heel region 4 is rising or lifting off from the sole 16 increasesthe amount of time that the heel region 4 is supported by the sole 16during gait movement. That is, the rising heel cup 130 decreases theamount of time that the heel region 4 is unsupported between theterminal stance (heel-off) and initial contact (heel-strike) phase ofgait. In other words, the heel region 4 is cradled and cupped by theheel cup 130 as the sole 16 dynamically rotates toward the heel region 4such that the heel cup 130 actively engages the heel region 4 even asthe heel region 4 is lifting upward.

For comparison, FIG. 11 illustrates a flat-soled flip-flop 12 donned onthe foot 2 at the terminal stance (heel-off) phase of gate. As shown,the heel region 4 has lifted away from the heel portion 122 of the sole16 and the heel region 4 is entirely or substantially entirelyunsupported in the transverse plane 154, the frontal plane 156, and thesagittal plane 158 by the sole 16 at least in the terminal stance. As aresult, the sole 16 dangles from the foot 2 between terminal stance(heel-off) and initial contact (heel-strike) phases which causescompensatory foot adjustment such as toe flexion/extension and/or footadduction/abduction. For example, the curved sidewall region 134 cancause the heel region 4 to align into the heel cup 130 along at leastalong the sagittal plane in terminal stance. Accordingly, the orthoticshell 10 can control foot 2 contact points and pressure along thesagittal plane in terminal stance via the heel cup 30 (and midfoot andforefoot portions 24, 26) as discussed herein. Further, the orthoticshell 10 via alignment and pressure of the heel cup 130 in terminalstance as discussed herein can control (e.g., substantially prevent orinhibit) roll of the foot 2 in the transverse plane relative to theorthotic/sandal.

For reference, as illustrated in FIG. 15, abduction 141 can refer tomotion that moves the foot 2 (e.g., the forefoot such as the foot areawith the toes) away from a center or vertical centerline of a body alongthe transverse plane 154 as illustrated by abduction direction 160.Stated differently, abduction 141 can refer to a motion that pulls thefoot 2 (e.g., the forefoot) away from the midline of the body along thetransverse plane 154 as illustrated by abduction direction 160.Adduction 142 can refer to motion that moves the foot 2 (e.g., theforefoot such as the foot area with the toes) toward a center orvertical centerline of a body along the transverse plane 154 asillustrated by adduction direction 162. Stated differently, adduction142 can refer to a motion that pulls the foot 2 (e.g., the forefoot)toward the midline of the body along the transverse plane 154 asillustrated by adduction direction 162.

In contrast, the flip-flop 12 fitted with the orthotic shell 10 of thepresent disclosure, provides a dynamic and reactively rotating sole 16which positions the heel cup 130 closer to the foot 2, which prolongsthe engagement between the wearer's heel region 4 and the heel cup 130of the sole 16. This allows for a more natural gait particularly in aflip-flop due to prolonged contact between the foot 2 and the sole 16.Accordingly, there is less need for compensatory foot adjustment such astoe flexion/extension and/or foot adduction/abduction. Further, theprolonged contact may decrease the effects of prolonged flip-flop usesuch as, but not limited to, shortening of the stride, ankledorsiflexion and toe fatigue due to curling of the toes in order tograsp the center post of the Y-shaped strap of the flip-flop. In otherwords, the muscles in the foot 2 may work less to retain the flip-flop12 on the foot 2, which may improve comfort and biomechanics of the footrelative to flat-soled flip-flops.

Accordingly, an increase in time of and extending heel region 4 support(by the heel cup 130 as discussed herein) into the terminal stance(e.g., increasing duration of contact ad support into terminal stance),minimizes the time (e.g., at least through part of the terminal stance)which a person, for example, curls their toes or otherwise exerts effortto retain the flip-flop 12 on the foot 2 in a desired position. Theassistance, even just for between 1 to 100 milliseconds, to hold theheel cup 130 to the heel region 4 via the orthotic shell 10 can helplessen toe strain, reduce foot fatigue, and improve gait. Further, theassistance to hold the heel cup 130 to the heel region 4 via theorthotic shell 10 can help prep for heel strike landing by having theflip-flop 12 in a better or more desired position (e.g., predeterminedposition even though the orthotic shell 10 may no longer be activelyassisting at heel strike.

The prolonged contact between the heel region 4 of the foot 2 and theheel cup 130 also prolongs the alignment between the foot 2 and the sole16. Accordingly, the heel cup 130 is more closely aligned and centeredwith the heel region 4 upon each heel strike. That is, the prolongedcontact shortens the amount of time that the foot 2 and the sole 16 areseparated between terminal stance (heel-off) and initial contact(heel-strike) phases. This may ensure that the heel cup 130 is moreclosely centered with the heel region 4 upon each heel-strike whencompared to a flat-soled flip-flop.

As described above, the heel cup 130 rotates and presses against theheel region 4 of the foot 2, which applies the terminal stance heelforce F_(TSH) upon the heel region 4 of the foot 2. As shown in FIG. 9,the terminal stance heel force F_(TSH) is applied at an angle α relativeto the midstance heel force F_(MSH). For comparison, the midstance heelforce F_(MSH) in FIG. 8 is applied to the heel region 4 by the heel cup130 in a substantially vertical direction. The heel cup 130 applies theterminal stance heel force F_(TSH) at the angle α due to the dynamicrotation of the heel cup 130 from the midstance (foot-flat) to terminalstance (heel-off) phases of gait. The angle α increases as the heel cup130 rotates due to the increase of the terminal stance arch forceF_(TSA) and the heel region 4 lifting away from and off the sole 16. Theangle α increases to a maximum angle α_(max) at the position where theheel region 4 is no longer in contact with the heel cup 130, as shown inFIG. 10. In other words, the magnitude of the terminal stance heel forceF_(TSH) equals zero. Accordingly, the maximum angle α_(max) defines themaximum range of rotation by the heel cup 130. In some embodiments, themaximum angle α_(max) may be a value between 15 degrees to 30 degrees,including the foregoing values and ranges bordering therein. In otherembodiments, the maximum angle α_(max) may be less than 15 degrees orgreater than 30 degrees.

The semi-rigid construction of the orthotic shell 10 allows the chordlength of the arch region 140 to vary in length such that the heel cup130 rocks and rotates dynamically during the loading response phase ofthe wearer's gait. Orthotic insoles formed from non-rigid materials suchas foam will merely compress downward under the weight of the wearer.That is, arch region of a foam orthotics would not increase in chordlength and facilitate rotation of the heel cup. Orthotic insoles formedfrom rigid materials lack the flexibility to allow flattening of thearch region and an increase in chord length to facilitate rotation ofthe heel cup. They are static in stance and not functional.

In some embodiments, the shape of the orthotic shell 10 may vary toprovide various levels of support to enhance the comfort and/orcompensate for accommodate a variety of foot abnormalities ordeformities. For example, in some embodiments, the forefoot portion 26may have metatarsal pads formed thereon to improve the comfort of theorthotic shell 10 within the forefoot portion 26.

In some embodiments, the shape of each of the heel portion 22, themidfoot portion 24 and the forefoot portion 26 may vary to accommodatethe shape of a wearer's foot. Similarly, the position of each of theheel, midfoot and forefoot portions 22, 24, 26 relative to each othermay vary to accommodate the shape of a wearer's foot.

In some embodiments, the orthotic shell 10 may have varying thicknessesbetween the heel, midfoot and forefoot portions 22, 24, 26. In someconfigurations, the thicknesses may be varied according to the desiredbending strength, torsional rigidity, stiffness, deflection amount, etc.of the orthotic shell 10. For example, the thickness in a region of theorthotic shell 10 may be thicker to reduce flexibility of the orthoticshell 10 within that region. Similarly, the thickness across the heel,midfoot and forefoot portions 22, 24, 26 may be varied such that theorthotic shell 10 may accommodate varus and valgus foot deformitiesand/or flexible and rigid foot deformities. Similarly, the heel, midfootand forefoot portions 22, 24, 26 may be formed from differing materialsor constructions such that the rigidity, stiffness and/or flexibility ofeach portion is optimized. In some embodiments, the heel, midfoot andforefoot portions 22, 24, 26 may comprise structural enhancers such as,but not limited to, ribs, pleats, fillets, recesses, etc. to providerigidity or flexibility in the desired portion.

In some embodiments, the orthotic shell 10 may be provided with a distalextension, angled extension, or distal angled lever 90 positionedforward of the front portion 62 of the forefoot portion 26 when viewedin the sagittal plane, as shown in FIG. 17. The distal extension portion90 may be angled relative to the forefoot portion 26 and extends awayfrom the front portion 62 of the forefoot portion 26. The distalextension portion 90 extends a distance in a direction towards themetatarsal heads and sulcus of the foot from the forefoot portion 26such that the distal extension portion 90 supports the metatarsal headsand sulcus of the foot. That is, the distal extension portion 90 has alength and a width such that the distal extension portion 90 engages themetatarsal heads and sulcus of the foot.

In some configurations, the distal extension portion 90 may have a widththat is similar or matches the width of the forefoot portion 26. Inother configurations, the distal extension portion 90 may have a widththat is narrower or wider than the width of the forefoot portion 26. Insome configurations, the distal extension portion 90 may have athickness that is similar or matches the thickness of the forefootportion 26. In other configurations, the distal extension portion 90 mayhave a thickness that is thinner or thicker than the thickness of theforefoot portion 26.

The distal extension portion 90 extends from the front portion 62 of theforefoot portion 26 so as to form a lever or rocker arm. In use, thedownward force of the foot sulcus and plantar metatarsal heads on thedistal extension portion 90 provide a lever effect and/or arocking-effect on the orthotic shell 10. That is, the downward force onthe distal extension portion 90 causes the heel cup 30 to move upwardsas the orthotic shell 10. The upward movement of the heel cup 30 iscaused by rocking or rotation about the front portion 62 of the forefootportion 26 such that the heel cup 130 and the arch region 140 of thesole 16 is rotated towards the foot 2. That is, in addition to thedynamic rotation of the heel cup 30 provided by the heel cup 130 of thesole 16 at terminal stance, the downward force of the foot sulcus andplantar metatarsal heads on the distal extension portion 90 causesfurther dynamic rotation of the sole 16 which increases contact of thesole 16 with the foot 2 beyond midstance and into the toe-off phase ofgait.

The rotation of the orthotic shell 10 caused by the distal extensionportion 90 prolongs the contact between the wearer's foot 2 and the heelcup 130 and the midfoot arch region 140 of the sole 16 of the flip-flop12 beyond midstance and into the toe-off phase of gait. That is, thiscontact further prolongs the contact into heel off and early swingphases of gait due to the foot sulcus and plantar metatarsal headspressing down on the distal extension portion 90. The closer and moreprolonged interface allows for a more natural gait due to better andprolonged contact and less need for compensatory foot/gait adjustmentsuch as shortened stride, increased cadence and toe flexion/extensionand or foot adduction/abduction.

In some embodiments, the distal extension portion 90 may extend towardsthe foot of the wearer at an angle θ relative to the forefoot portion 26or a portion of the forefoot portion 26 near the end of the forefootportion 26. As illustrated in FIG. 17, the distal extension portion 90may be angled upward to extend at least in part toward insole portion 18or away from outsole portion 20 (and toward a front of the sole 16). Insome embodiments, the angle θ of the distal extension portion 90 may bea value between 15 degrees to 30 degrees, including the foregoing valuesand ranges bordering therein. In other embodiments, the angle θ may beless than 15 degrees or greater than 30 degrees.

In some embodiments, the distal extension portion 90 may have athickness similar to the heel, midfoot and forefoot portions 22, 24, 26.In other embodiments, the distal extension portion 90 may vary inthickness relative to the heel, midfoot and forefoot portions 22, 24, 26according to the desired bending strength, torsional rigidity,stiffness, deflection amount, etc. of the orthotic shell 10 as discussedherein. For example, the thicker or relatively thicker the heel, midfootand/or forefoot portions 22, 24, 26, the greater the thickness of thedistal extension portion 90. Or the thinner or relatively thinner theheel, midfoot and/or forefoot portions 22, 24, 26, the thinner thethickness of the distal extension portion 90. Or the thinner orrelatively thinner the heel, midfoot and/or forefoot portions 22, 24,26, the thicker the thickness of the distal extension portion 90. Or thethicker or relatively thinner the heel, midfoot and/or forefoot portions22, 24, 26, the thinner the thickness of the distal extension portion90. In some embodiments, the distal extension portion 90 may vary inthickness along its length and width to provide the desired bendingstrength, torsional rigidity, stiffness, deflection amount, etc. of thedistal extension portion 90.

In some embodiments, a portion of the distal extension portion 90 mayhave a curved shape so as to facilitate and/or encourage the rockingmotion of the orthotic shell 10. For example, an underside of the distalextension portion 90 (i.e., a portion of the distal extension portion 90facing the outsole portion 20) may be curved such that the orthoticshell 10 is able to roll along the curvature when the downward force onthe distal extension portion 90 is applied by the foot sulcus andplantar metatarsal heads. The rolling along the curvature may provide agradual rocking motion which further prolongs the contact into heel offand early swing phases of gait. In other embodiments, an entirety of thedistal extension portion 90 may have a curved shape. In someembodiments, the shape and geometry of the curvature may vary along thelength, width and thickness directions of the distal extension portion90 and/or the orthotic shell 10 to provide the desired amount, range andrate of rocking motion.

In some embodiments, the sole 16 can be molded around the orthotic shell10 as opposed to being sandwiched between the insole and outsoleportions 18, 20 of the sole 16. For example, in some embodiments, duringthe injection molding process of the sole 16, the orthotic shell 10 maybe inserted into the mold cavity such that the sole 16 is formed ontoand/or around the orthotic shell 10. Similarly, in other embodiments,either one of the insole and outsole portions 18, 20 can be first moldedaround the orthotic shell 10 and bonded to the other of the insole andoutsole portions 18, 20. For example, the insole portion may be formedonto the orthotic shell 10 such that the orthotic shell 10 comprises atleast a portion of the outsole portion 20. As another example, theorthotic shell 10 may be part of or form the insole portion 18 and mayhave direct or at least partial direct contact with the foot 2.Accordingly, the orthotic shell 10 would not be enclosed and may beexternally visible when the sole is fully assembled.

In some embodiments, the orthotic shell 10 may be shaped such that theheel portion 24 is rotated relative to the midfoot portion 24 and theforefoot portion 26. FIGS. 12A, 12B, and 12C illustrate the orthoticshell 10 with respect to the transverse plane 154. As shown, the heelcup 30 is rotated relative to the midfoot portion 24 and the forefootportion 26 such that a longitudinal centerline 80 of the heel cup 30forms an angle β relative to the longitudinal centerline 82 of the heelcup 30. FIG. 12A illustrates the heel cup rotate towards the lateralside 44 of the orthotic shell 10. FIG. 12B illustrates the heel cuprotate towards the medial side 42 of the orthotic shell 10. In someembodiments, the angle β may be a value between 5 degrees to 15 degrees,including the foregoing values and ranges bordering therein. In otherembodiments, the maximum angle β may be less than 5 degrees or greaterthan 15 degrees. The rotated heel cup 30 or the orthotic shell 10 mayaccommodate wearers having adduction/abduction of the midfoot andforefoot. FIG. 12C illustrates an embodiment of the orthotic shell withrespect to the transverse plane with the heel cup rotated either towardthe medial side or toward the lateral side of the orthotic shell.

FIGS. 12A, 12B, and 12C illustrate the orthotic shell 10 with respect tothe transverse plane 154. In some embodiments, the orthotic shell 10 maybe shaped such that the heel portion 24 is rotated or protruded (bulged)relative to the midfoot portion 24 and the forefoot portion 26. In someembodiments, the orthotic shell 10 may be shaped such that the heelportion 24 is rotated or protruded (bulged) about 1 mm to 10 mm relativeto the midfoot portion 24 and the forefoot portion 26. In someembodiments, the orthotic shell 10 may be shaped such that the heelportion 24 is rotated or protruded (bulged) about 0.5, 1, 2.5, 5, 7.5,10, 12.5, 15, 17.5, or 20 mm, or a value within a range defined by anytwo of the aforementioned values relative to the midfoot portion 24 andthe forefoot portion 26.

In some embodiments, each of the heel portion 24, the midfoot portion 24and the forefoot portion 26 may be rotated relative to each othertowards the medial side 42 or the lateral side 44 of the orthotic shell10. Similarly, each of the heel portion 24, the midfoot portion 24 andthe forefoot portion 26 may be rotated relative to each other in thetransverse plane 154, the frontal plane 156, and the sagittal plane 158.Accordingly, the orthotic shell 10 may have a shape that providesorthotic support to a variety of shapes of wearers' feet.

Soloha Orthotic

In some embodiments, the orthotic is a Soloha orthotic (FIGS. 18A-18H,and Example 1). In some embodiments, the orthotic can be customized to aperson's foot, for example, impression casted, scanned, photographed, 3Dprinted, and the like. In some embodiments, the orthotic can be used asa removable shoe orthotic. In some embodiments, the orthotic can be usedas a transferable shoe orthotic. In some embodiments, the Solohaorthotic can be used as a removable and transferable shoe orthotic.

A embodiment of the Soloha orthotic is shown in FIGS. 18A-18H. In someembodiments, the orthotic (e.g., a Soloha orthotic) allows fordeflection to occur with midfoot loading of the transverse arch of thefoot. In other words, the arched shank of the Soloha orthotic isconfigured such that when a downward force is applied on the archedshank the arched shank deflects in such a way that the heel cup of theorthotic is reactively rotated toward the heel region of the foot. Asshown in FIG. 9, the heel cup 130 rotates and presses against the heelregion 4 of the foot 2, which applies the terminal stance heel forceF_(TSH) upon the heel region 4 of the foot 2. The terminal stance heelforce F_(TSH) is applied at an angle α relative to the midstance heelforce F_(MSH). For comparison, the midstance heel force F_(MSH) in FIG.8 is applied to the heel region 4 by the heel cup 130 in a substantiallyvertical direction. The heel cup 130 applies the terminal stance heelforce F_(TSH) at the angle α due to the dynamic rotation of the heel cup130 from the midstance (foot-flat) to terminal stance (heel-off) phasesof gait. The angle α increases as the heel cup 130 rotates due to theincrease of the terminal stance arch force F_(TSA) and the heel region 4lifting away from and off the sole 16. The angle α increases to amaximum angle α_(max) at the position where the heel region 4 is nolonger in contact with the heel cup 130, as shown in FIG. 10. In otherwords, the magnitude of the terminal stance heel force F_(TSH) equalszero. Accordingly, the maximum angle α_(max) defines the maximum rangeof rotation by the heel cup 130. In some embodiments, the maximum angleα_(max) may be a value between 15 degrees to 30 degrees, including theforegoing values and ranges bordering therein. In other embodiments, themaximum angle α_(max) may be less than 15 degrees or greater than 30degrees. In some embodiments, the maximum angle α_(max) may rangebetween 10 degrees to 35 degrees. In some embodiments, the maximum angleα_(max) is about 5, 10, 15, 20, 25, 30, 35, or 40 degrees, or a valuewithin a range defined by any two of the aforementioned values.

The following example is non-limiting.

Example 1—Gait Exam Comparison Between Standard Flip-Flop Sandal andSoloha Orthotic Sandal

Potential adverse gait changes caused by wearing flip-flops compared towearing normal shoe gear on manmade surfaces is typically noted usingfour (4) parameters: Stride Length (SL), Ankle Attack Angle (AAA),Stance Time (ST) and Frontal Plane Control of the Heel (FPCH). In thisstudy, also included were abnormalities of Extensor and FlexorSubstitution as well as Abductor Twist which appear in most flip flopgait examinations—these are typically seen in abnormal barefoot gaitevaluations and are exaggerated in flip-flops due to compensations.

Standard flip flops cause a comparative shortened Stride Length, LargerAnkle Attack Length, Shorter Stance Time and minimal to no Frontal PlaneHeel Control as well as Extensor/Flexor Substitution and Abductor Twist.

Four persons of normal BMI and without any history of lower extremitypathology were gait examined with standard flip-flops compared to Solohaorthotic sandals on both feet. One male and one female with forefootvalgus reducible cavo-varus foot types and one male and one female withforefoot varus reducible plano-valgus foot types.

All four patients in gait analysis exhibited a visual improvement whenwearing the Soloha sandals compared to the standard flip-flop in three(3) of the four (4) standard parameters; SL, ST and FPCH as well asreduction of Flexor Substitution in swing phase and near eliminationAbductor Twist. AAA was difficult to assess visually but appeared to beslightly increased in the cavus foot types and less in the planus foottypes. Heel strike contact was invariably centered in the Soloha wherein the standard flip-flop heel strike was consistently medially offcenter.

The Soloha sandal provided a more normal “shod foot gait” when comparedto standard flip-flops with visual gait exam that exhibited a longerStride Length, longer Stance Time and significant Frontal Plane HeelControl in both foot types, male and female with reduced maximal heeleversion and inversion. The Soloha sandal gait appeared more stable andpropulsive and with improved patellar tracking than that of the standardflip-flop gait.

All four participants indicated significant improved comfort andstability in the Soloha sandal compared to the standard flip-flop.

Although embodiments have been shown and described herein as a flip-flopsandal or components for a flip-flop sandal, it is appreciated thataspects and features of the embodiments may be applied to a wide rangeof footwear, including without limitation, athletic shoes, casual shoes,dress shoes, work boots and recreational footwear.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosure. Indeed, the novel methods and systems describedherein may be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the describedmethods and systems may be made without departing from the spirit of thedisclosure. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the disclosure.

What is claimed is:
 1. An orthotic device for footwear worn on a foot ofa wearer, the orthotic device comprising: a heel portion configured tosupport a heel region of the foot, and a midfoot portion connected tothe heel portion and configured to support an arch region of the foot,the midfoot portion comprising an arched shank having a curved convexshape, wherein the arched shank is configured to deflect under adownward force applied thereon which increases a chord length of thearched shank in a longitudinal direction, and wherein the increase inthe chord length causes reactive rotation of the heel portion toward theheel region of the foot.